Securing a PDF document is often required to keep the data in the document available for authorized persons only, to restrict access to specific parts of the document or to prohibit modifying, printing or sharing the secured document by unauthorized persons. Also, PDF security assures the authorship of the document, prevents falsification and forging of the document thus ensuring the document really comes from its author.
There are four PDF security instruments in Master PDF Editor:
Encryption with a password
Encryption with a certificate
Signing with a certificate
Redacting a PDF document